20cm离子推力器放电室流场计算模拟

Flow field simulation of 20cm diameter ion thruster discharge chamber

为了优化20cm离子推力器放电室内部推进剂供气方式，研究了在不发生气体放电时，推力器阳极和主阴极供气接口处的流体速度和压强，并以此开展推力器放电室内部的流场计算。结果表明：采用单阳极供气管方式，阳极出口处压强为4～158Pa，气流出口速度为0．1～47m／s；阴极小孔出口处的压强约为33．1Pa，出口速度约为12m／s；考虑真空系统的返流作用时，单阳极供气管方式下放电室内部压强为0．OOl～0．4Pa，大部分区域Xe原子数密度为（O．2～3）×10^18／m3，在靠近栅极的部分区域数密度达到9×10^19／m3左右；在增加阳极组件的供气管数量后，阳极的气体出口速度为18-40m／s，放电室压强为0．03～O．1Pa，大部分区域Xe原子数密度为（0．72～2．4）×10^19／m3，靠近阳极与主阴极进气端的小部分区域原子数密度约2×10^17／m3，且放电室内部原子密度整体分布较为均匀。

In order to optimize the feeding way of the propellant into the 20 cm diameter ion thruster＇s discharge chamber, the fluid velocity and pressure at the interface of the thruster anode and main cathode were studied without discharge process, and then the fluid field inside the discharge chamber was calculated. The results indicate that the pressure at the outlet of the thruster＇ s anode gas feeding component is in the range of 4-158 Pa, the exiting velocity of the gas flow is approximately in the range of 0. 1-47 m/s, The pressure at the outlet of the cathode aperture is approximately 33.1 Pa, and the velocity is approximately 12 m/s. considering the backstreaming of the vacuum system, the pressure inside the discharge chamber in the range of 0. 001-0.4 Pa, the density distribution of Xe atom is not uniform and in the range of （0.2-3） × 1018 m-3 , the density near grids assembly is about 9 × 1019 m-3. With the addition of a number of anode feeding pipes, the exiting velocity of the anode gas feeding component is in the range of 18-40 m/s, and the pressure inside the discharge chamber in the range of 0.03-0.1 Pa. When the density of Xe atoms in most part of the discharge chamber is about （0.72-2.4） × 10^19 m 3, the atom density in a small part near the anode and the main cathode＇s gas-in end is of the order of 2 × 1017 m^-3 and the discharge has a relatively overall uniform density distribution.